Ophthalmological surgery continues to evolve towards smaller instruments that produce smaller incisions. The most common incision size currently is 20 gauge (approximately 1.0 mm diameter), but newer instruments as small as 27 gauge (approximately 0.41 mm diameter) are being utilized, and smaller instruments are likely in the future. The advantages of smaller incisions are multiple, including lessened trauma, faster healing, faster wound management (no sutures), and greater patient comfort.
Problems exist with the smaller instruments, however. The small diameter of the instruments makes them quite flexible, which is a disadvantage for the surgeon. With larger diameter instruments, there is very little “play”, so the tips of the instruments go exactly where the surgeon desires that they go. With the smaller diameter instruments, the tips can move from their intended positions due to the bending or flexing of the fine wire-like instruments, which makes the surgeon feel a loss of control.
Bending or flexing of the small instruments is of particular concern in some procedures, for example, removal of peripheral vitreous, when the eye must be turned to allow viewing by the surgeon. Turning of the eye is accomplished by moving the instrument relative to the patient's head while a portion of the instrument remains inserted within a portion of the eye. Because the amount of flexing of the instrument is relatively large and unpredictable to the surgeon, precise repositioning of the eye becomes more difficult. In addition, delicate maneuvers such as peeling membranes from the retinal surface become significantly more difficult when instruments are too flexible causing imprecision of movements.
What is needed is an instrument design that accommodates increasingly small diameters, and still provides precise control without unwanted flexing.